TR.20.3 Tapered Member Specification
The following commands are used to specify section properties for tapered I-shapes.
General Format
argument-list = f1 f2 f3 f4 f5 (f6 f7)
Where:
| Parameter | Description |
|---|---|
| f1 | Depth of section at start node. Must be greater than f3. |
| f2 | Thickness of web. |
| f3 | Depth of section at end node. |
| f4 | Width of top flange. |
| f5 | Thickness of top flange. |
| f6 | Width of bottom flange. Defaults to f4 if left out. |
| f7 | Thickness of bottom flange. Defaults to f5 left out |
Notes
- All dimensions (f1, f2, … f7) should be in current units.
- f1 (Depth of section at start node) should always be greater than f3 (Depth of section at end node). You must provide the member incidences accordingly.
- Shear deformation is not considered for tapered I-Beams and tapered poles. This means that the SET SHEAR command has no effect on the deformation computed for members with these cross sections.
Example 2
The following example demonstrates the design of a doubly-symmetric, tapered I section.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 31-Jul-14
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
2 0 3 0; 3 3 3 0;
MEMBER INCIDENCES
2 2 3;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
2 TAPERED 0.4 0.008 0.3 0.15 0.125 0.15 0.125
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
2 FIXED
LOAD 1 LOADTYPE Dead TITLE LOAD CASE 1
MEMBER LOAD
2 UNI GY -0.5
2 CON GY -10
2 CMOM GZ -50 3
LOAD 2 LOADTYPE Live TITLE LOAD CASE 2
MEMBER LOAD
2 UNI GY -10
2 CON GY -15
2 CMOM GZ -500 3
JOINT LOAD
3 FX -10
PERFORM ANALYSIS
SECTION 0.25 0.5 0.91667
PRINT MEMBER SECTION FORCES ALL
LOAD LIST 1 2
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
TRACK 2 ALL
CHECK CODE ALL
PARAMETER 2
CODE AISC UNIFIED 2010
METHOD ASD
TRACK 2 ALL
CHECK CODE ALL
FINISH